1. Field
This invention relates to lightheads containing multiple individual spotlights. It is specifically directed to means for adjusting the direction of light beams emanating from such individual spotlights, and provides an improved mechanism for synchronizing the movement of the individual spotlights from one or more remote locations.
2. State of the Art
Lighthead assemblies with multiple individual spotlights have long been used to provide a substantially shadowless illumination of a work area. A classic application of such assemblies is for the illumination of surgical operating sites. Lighthead assemblies with multiple spotlights evolved as an improvement over earlier operating room lighting fixtures which included expedients to scatter or diffuse the light from a single source. U.S. Pat. No. 1,909,947 illustrates an early arrangement of two spotlights with synchronized adjustment means. According to that arrangement, rotation of a central handle moves linkage structure which tilts the individual spotlights to change the direction of the light beams emanating therefrom. The light beams are thus caused to intersect (converge) at a selected distance from the spotlights. In this fashion, the shadow cast upon the illuminated area is reduced as compared to the shadow inherent with single source illumination. U.S. Pat. No. 3,055,087 discloses a more refined multi-beam lighthead assembly which provides synchronous orientation of a plurality of light beams by means of a cylindrical ring coupled by cam slots to individual spotlights arranged around the perimeter of the ring. U.S. Pat. No. 3,887,801 discloses another multi-beam lighthead assembly with a synchronized focusing mechanism. In this arrangement, a central cam ring is rotated by a handle axially disposed with respect to the assembly. The disclosures of U.S. Pat. Nos. 3,005,087 and 3,887,801 are incorporated by reference as portions of this disclosure for their detailed discussions of surgical lights with adjustable multi-beam lighthead assemblies, the objectives of such assemblies, and the mechanical linkages heretofore relied upon to effect synchronous linear shifting of the light beams emanating from multiple spotlights within the lighthead.
The various lighthead assemblies in current use have certain limitations and disadvantages. In a surgical setting, it is important for scrubbed personnel who are actually involved in a surgical procedure to be able to adjust (focus) the illumination resulting from the intersecting individual light beams. For this purpose, a centrally disposed handle, usually oriented parallel the central axis of the lighthead, is optimal. Such a handle must be capable of sterilization, and cannot be permitted to become contaminated during a procedure without imposing the concurrent constraint on scrubbed personnel of avoiding further handle contact. In many instances, however, it is either necessary or convenient for non-scrubbed personnel to focus the illumination while the surgical procedure is in progress. Such personnel cannot be permitted to contact a focusing handle which is required to remain uncontaminated. Currently available lighthead assemblies are not sufficiently adaptable to accommodate to these conflicting demands.
The synchronized focusing arrangements suggested to date have been structured with individual spotlights arranged in a circle, dedicating the region circumscribed by the lights to mechanical components. This arrangement limits the illumination obtainable at the center of an illuminated site and also limits the gradation of illumination obtainable from the center to the peripheral areas of the illuminated site.